On the 86 vert we are working on for my dad . When you first start it , it will jump to about 2000 rpm , then immediatly die , if you give it some gas it runs fine untill you let off the gas , then it dies. Once you do this though you can start the car and it will sit and idle fine at 900 rpm . I have double and triple checked for vaccum leaks, we did put new valve cover gaskets , intake and tb gaskets , new egr valve and gasket , cleaned IAC . New plugs, rotor, cap ,wires, o2 sensors ,fuel and air filter also . Timing is at 10 degrees . Car is still speed density and is an auto . Any suggestions?